Fuel injection nozzle for high-speed internal-combustion engines



Jan. 11, 1955 SONDEREGGER 2,699,358

FUEL INJECTION NOZZLE FOR HIGH-SPEED INTERNAL-COMBUSTION ENGINES Filed July 11, 1951 United States Patent FUEL INJECTION NOZZLE FOR HIGH-SPEED INTERNAL-COMBUSTION ENGINES Konrad Sonderegger, Winterthur,

to Schweizerische Lokomotivund Maschinenfabrik, 'Winterthur, Switzerland, 2 Swiss company Application July 11, 1951, Serial No. 236,107 Claims priority, application Switzerland July 18, 1950 1 Claim. (Cl. 299-107.6)

Switzerland, assignor Known nozzles of this type fail to satisfy in high-speed engines because the atomization of the fuel in the short injection time available is length of the nozzle holes arranged circularly at these points is not more than twice their respective diameters. By forming the nozzle head with this locally thin wall, the nozzle holes are made so short that the fuel emerges from the nozzle in substantially wider-angle cones of spray. The core of the jet is reduced in proportion to the entire mass of the jet, and the wider-angle cone of spray can now seize and entrain a larger quantity of air.

A further advantage of this arrangement of the nozzle the fact that the cones of fuel spray emerging from the nozzle holes are relatively short and are therefore unable to impinge on the walls of the combustion chamber, where they would otherwise form incrustations.

Since with the thickness of the shell of the nozzle head reduced in th is way the removal of heat is someately above the nozzle-hole outlets, because in this case the portion of the nozzle head which still projects into the combustion chamber will, owing to the reduction of surface, absorb less heat from the combusinto the cooled nozzle-holder.

The drawing illustrates a typical embodiment of the invention.

Fig. 1 shows the lower part of an injector in longitudinal section, and

Fig. 2 shows the head of the scale, likewise in longitudinal section.

The injector is part of an air-cooled internal combustion engine and is, to enable it to be cooled by the stream of combustion air entering the engine, located in the air intake port 1a of the cylinder head 1. The internal parts of the injector are accommodated in a cooling jacket 2, made of material of high coefiicient of heat-conductivity, which in turn is provided with cooling fins or ribs 3 and is sealed at the bottom of the cylinder head by means of a heat-insulating packingsea 4.

The nozzle-holder 5 secured in the upper portion of the cylinder head 6 wh' 7 inserted therebetween, by the cap not 8. The hydraulically controlled nozzle needle 10 urged by the spring 9 bears with its lower end 11 against the inner wall of the nozzle head 12.

The fuel oil delivered by a fuel pump is supplied to the nozzle head through ports 13 and slit filters 14 and, when the injection pressure is reached, lifts the nozzle injector on an enlarged needle 10 by the shoulder 15 the spring 9.

As is shown on an enlarged scale in Fig. 2, the tip 11 of the nozzle valve needle projects into a cylindrical bore with a hemispherically-shaped lower limiting surface 16, the tip of the needle being located approximately in the centre M of the hemisphere. On the outside the nozzle head is of conical shape, its angle of conicity being about both in the seating 17 and at the point the nozzle holes 19 pass exactly through 16 and are exactly peragainst the pressure of coohng sleeve or acket 2 1s extended that the distance e is not more than twice the dlameter d of the holes. Accordingly, the nose 18 of the nozzle projects only by the amount a into the combustion chamber and exposes a correspondingly small heat-absorbing surface to the hot gase quantity of heat as still does penetrate into said nozzle holes, seating 17, directly rows 20).

It can thus be seen that in accordance with the present invention there has been provided a fuel-injector device for high-speed and air-cooled combustion engines transferred, in the taper into the cooling jacket 2 (see armunication with said space.

Having thus described the invention, what is claimed as new and dcslred to be secured by Letters Patent, is:

and having a cylindrical hollow forward end portion with an inner seating surface, a needle-operated fuel nozzle terminating in a head disposed within said forward end portion of said cooling jacket, said nozzle head being provided with a conically d inner seating surface and with a continuous and comcally shaped outer survided with nozzle openings passing through said tip and directed toward said combustion chamber, the remainder of said outer surface of sa1d nozzle head being positioned rearwardly of said tip and acket, the forward end of said needle being disposed rearwardly of said nozzle tip and engageable with said inner seating surface in said nozzle head, so that, when said tip and said openings extend beyond said inner seating surface of said forward end portion of said cooling jacket into said combustion chamber, said needle end is located remote from said nozzle tip, said end portion of said cooling jacket extending through said bore of said cylinder head and providing a space therebetween, said cylinder head and said cooling jacket being provided with shoulders, and heat-insulating packing means seated intermediate said shoulders and in communication with said space.

References Cited in the file of this patent UNITED STATES PATENTS 

